Serial Number/Date Code Sequence
The date that a unit was manufactured can be determined by looking at the unit serial number. Compare
the unit serial number to the three examples below (manufactured in 1970-77, 1978-92, or 1993-current).
Once you’ve determined which of the three serial number sequences the unit serial number most closely
resembles, then look for the number or letters, which identify the date of manufacture.
For units produced from 1970 through 1977:
15
A
67
A
098
15 = Day
A = Month (see Months list below)
67 = Year Reversed (ex: 67 = 1976)
J = Factory Location (J = Bellevue, Ohio and A = Columbus, Ohio)
A = N/A
Months
098 = Sequential Serial Number That Day
A =Jan
B =Feb
C =Mar
D =Apr
E =May
F =June
G =July
H =Aug
J =Sept
K =Oct
L =Nov
M =Dec
For units produced from 1978 through 1992:
Years
C
89274 A
A
C
8 = 1978
F = 1985
C = Sequence Code Letters
9 = 1979
G = 1986
89274 = Serial Number
A = 1980
H = 1987
A = Month (See Months list below)
B = 1981
J = 1988
A = Year (See Years list at right)
C = 1982
K = 1989
C = Factory Location (See Location list below)
D = 1983
L = 1990
E = 1984
M = 1991
N = 1992
Months
Location
A = Jan
B = Feb
C = Mar
D = Apr
A = Armstrong
E = May
F = June
G = July
H = Aug
B = Bellevue, Ohio
J = Sept
K = Oct
L = Nov
M = Dec
C = Columbus, Ohio
For units produced since January 1993:
84
95
A
12345
84 = Factory (16 = Orangeburg, 56 = Lennox, 60 = Coils, 84 = Armstrong)
95 = Year (ex: 1995)
A = Month (see Months list at right)
12345 = Sequential Number
Months
A = Jan
B = Feb
C = Mar
D = Apr
E = May
F = June
= July
H = Aug
J = Sept
K = Oct
= Nov
M = Dec
Ducane serial number nomenclature
0183290431
- Old style units
018329 are computer generated by sequence
04
year unit was manufactured
31
Week of the year or the end of August
Week
01-04 January
27-30 July
05-08 February
31-34 August
09-13 March
35-39 September
14-17 April
40-43 October
18-21 May
44-47 November
22-26 June
48-52 December
4601J19567 – New style units
46 Plant of Manufacture or Blackville
01 Year of Manufacture
J Month of Manufacture (Note: the Letter I is not used)
Plants
46 Blackville
84 Bellevue
16 Allied Orangeburg
60 ADP
56 Lennox
Months
A = Jan
B = Feb
C = Mar
D = April
E = May
F =June
G = July
H = Aug
J = Sept
K = Oct
L = Nov
M = Dec